Title:Effectiveness of Quenchers to Reduce Radiolysis of 111In- or 177Lu-Labelled Methionine-Containing Regulatory Peptides. Maintaining Radiochemical Purity as Measured by HPLC
Volume: 12
Issue: 23
Author(s): Erik de Blois, Ho Sze Chan, Mark Konijnenberg, Rory de Zanger and Wouter A.P. Breeman
Affiliation:
Keywords:
gastrin releasing peptide, HPLC, minigastrin, quenchers, radiochemical purity, radiolysis, methionine, regulatory
peptides
Abstract: An overview how to measure and to quantify radiolysis by the addition of quenchers and to maintain Radio-
Chemical Purity (RCP) of vulnerable methionine-containing regulatory peptides is presented. High RCP was only
achieved with a combination of quenchers. However, quantification of RCP is not standardized, and therefore comparison
of radiolabelling and RCP of regulatory peptides between different HPLC-systems and between laboratories is cumbersome.
Therefore we suggest a set of standardized requirements to quantify RCP by HPLC for radiolabelled DTPA- or
DOTA-peptides. Moreover, a dosimetry model was developed to calculate the doses in the reaction vials during radiolabelling
and storage of the radiopeptides, and to predict RCP in the presence and absence of quenchers. RCP was measured
by HPLC, and a relation between radiation dose and radiolysis of RCP was established. The here described quenchers are
tested individually as ƒ(concentration) to investigate efficacy to reduce radiolysis of radiolabelled methionine-containing
regulatory peptides.
